A series resonant oscillator based on coupled inductors

Abstract

The application discloses a series resonant oscillator based on coupled inductance, which comprises four resonant cavities with the same structure and four driving units with the same structure, wherein mutual inductance coupling is formed between the first and third resonant cavities to form a differential output resonant cavity, and mutual inductance coupling is formed between the second and fourth resonant cavities to form a differential output resonant cavity; the output of the first resonant cavity is used as the input of the second and third driving units, the output of the second resonant cavity is used as the input of the third and fourth driving units, the output of the third resonant cavity is used as the input of the first and fourth driving units, and the output of the fourth resonant cavity is used as the input of the first and second driving units, thereby forming a loop, and the phase of the voltage signals output by the first to fourth resonant cavities is 0°, 90°, 180° and 270° in sequence; while the four-phase output is reserved, the chip area is reduced.

Description

Technical Field

[0001] This invention belongs to the field of radio frequency integrated circuits, and specifically relates to a series resonant oscillator based on a coupled inductor. Background Technology

[0002] In wireless communication systems, the frequency source is a fundamental core component, and breakthroughs in its key phase noise performance are of great significance to high-order modulation systems. The phase noise performance of the frequency source is mainly determined by its core module, the voltage-controlled oscillator (VCO). A low-phase-noise VCO is fundamental to realizing a low-phase-noise frequency source.

[0003] Series resonance technology reduces the resonant cavity impedance through an inductor-capacitor series resonant network, thereby reducing phase noise and increasing power consumption without increasing the supply voltage. Compared to traditional parallel resonant oscillator topologies, series resonant oscillators can achieve 20log... 10 (Q)dB of phase noise improvement, where Q is the quality factor of the resonant cavity.

[0004] In 2018, the University of Padua in Italy reported a four-phase series resonant oscillator chip, which achieved a four-phase output series resonant oscillator through a four-stage series resonant network. In 2024, Tsinghua University further suppressed phase noise by replacing the inductors in each stage of the original four-stage series resonant network with transformers. In 2025, South China University of Technology reduced the chip area and expanded the frequency tuning range by changing the four-stage series resonant network to a two-stage series-parallel network.

[0005] Because the phase feedback of a series resonant oscillator is 90°, four cascaded stages are required to meet the requirement of a total phase feedback of 360° from input to output and back to input. Therefore, compared to traditional cross-coupled oscillators, series resonant oscillators require four times the inductance, have a larger chip area, and currently have poorer overall performance. Summary of the Invention

[0006] Purpose of the invention: The purpose of this invention is to provide a series resonant oscillator based on coupled inductors, which reduces chip area while retaining four phase outputs.

[0007] Technical solution: The present invention provides a series resonant oscillator based on a coupled inductor, comprising:

[0008] Four resonant cavities with identical structures are designated as the first resonant cavity, the second resonant cavity, the third resonant cavity, and the fourth resonant cavity. The first resonant cavity and the third resonant cavity are mutually inductively coupled to form a differential output resonant cavity, and the second resonant cavity and the fourth resonant cavity are mutually inductively coupled to form a differential output resonant cavity.

[0009] Four identical driving units are designated as a first driving unit, a second driving unit, a third driving unit, and a fourth driving unit. The first driving unit outputs a first current signal to a first resonant cavity, which converts the first current signal into a first voltage signal. This first voltage signal serves as the input signal for both the second and third driving units. The second driving unit outputs a second current signal to a second resonant cavity, which converts the second current signal into a second voltage signal. This second voltage signal also serves as the input signal for both the third and fourth driving units. The third driving unit outputs a third current signal to a third resonant cavity, which converts the third current signal into a third voltage signal. This third voltage signal serves as the input signal for both the fourth and first driving units. The fourth driving unit outputs a fourth current signal to a fourth resonant cavity, which converts the fourth current signal into a fourth voltage signal. This fourth voltage signal serves as the input signal for both the first and second driving units. The first and third voltage signals form a differential signal, as do the second and fourth voltage signals. The phases of the first, second, third, and fourth voltage signals are 0°, 90°, 180°, and 270°, respectively.

[0010] Optionally, the first, second, third, and fourth resonant cavities each include an inductor L1 and a frequency tuning module. The two ends of the inductor L1 are connected to the input and output ports of the resonant cavity, respectively. The output terminal of the frequency tuning module is connected to the output port of the resonant cavity, and the control terminal is connected to the control voltage V. CON The third terminal is connected to the third terminal of another frequency tuning module located in the same differential output resonant cavity; the inductors L1 of the first resonant cavity and the third resonant cavity are mutually coupled, and the inductors L1 of the second resonant cavity and the fourth resonant cavity are mutually coupled. The frequency tuning module is used to adjust the frequency of the output voltage signal of each resonant cavity.

[0011] Optionally, the frequency tuning module includes a switched capacitor array and a variable capacitor array. One end of the switched capacitor array is connected to the output port of the resonant cavity, and the other end is connected to the third terminal of the frequency tuning module. One end of the variable capacitor array is connected to the output port of the resonant cavity, and the other end is connected to the control terminal of the frequency tuning module.

[0012] Optionally, the switched capacitor array includes a second capacitor C1 and multiple switched capacitor series modules connected in parallel, wherein each switched capacitor series module includes a first capacitor C connected in series. SCA And switch SW1, the other end of switch SW1 is connected in series with another switch SW1 located in the same differential output resonant cavity, and the first capacitor C SCA The other end is connected to the output port of the resonant cavity, and the second capacitor C1 is connected in parallel with the switch SW1; the variable capacitor array includes a third capacitor C2 and a variable capacitor C connected in series.var Variable capacitor C var The other end is connected to the control voltage V CON Connect the other end of the third capacitor C2 to the output port of the resonant cavity.

[0013] Optionally, the other end of switch SW1 is connected in series with another switch SW1 located in the same differential output resonant cavity and grounded.

[0014] Optionally, the frequency tuning module also includes a resistor R. B2 resistance R B2 One end is connected to the third capacitor C2 and the variable capacitor C var The series connection point is connected, and the other end is connected to the voltage V. B2 connect.

[0015] Optionally, the first resonant cavity, the second resonant cavity, the third resonant cavity, and the fourth resonant cavity each further include a fourth capacitor C. D1 Two fourth capacitors C are connected in series between the input ports of the first and third resonant cavities. D1 Two fourth capacitors C are connected in series between the input ports of the second and fourth resonant cavities. D1 .

[0016] Optionally, the first resonant cavity, the second resonant cavity, the third resonant cavity, and the fourth resonant cavity also include a fifth capacitor C. D2 The fifth capacitor C D2 It is connected in parallel across the inductor L1.

[0017] Optionally, the first resonant cavity, the second resonant cavity, the third resonant cavity, and the fourth resonant cavity also include a fifth capacitor C. D2 The fifth capacitor C D2 It is connected in parallel across the inductor L1.

[0018] Optionally, the first driving unit, the second driving unit, the third driving unit, and the fourth driving unit each include two transistors and two capacitors C. G and two resistors R B1 The source of the first transistor M1 in the first driving unit is connected to the drain of the second transistor M2, and the connection point is also connected to the input port of the first resonant cavity; the drain of the first transistor M1 is connected to the power supply, and the gate is connected in series with a capacitor C. G It is then connected to the output port of the fourth resonant cavity, and the gate is connected to the voltage V. B1 series resistor R B1 The source of the second transistor M2 is grounded, and its gate is connected in series with capacitor C. G It is then connected to the output port of the second resonant cavity, and the gate is connected to the voltage V. B1 series resistor R B1 ;

[0019] The source of the third transistor M3 in the second driving unit is connected to the drain of the fourth transistor M4, and the connection point is also connected to the input port of the second resonant cavity; the drain of the third transistor M3 is connected to the power supply, and its gate is connected in series with a capacitor C. G It is then connected to the output port of the first resonant cavity, and the gate is connected to the voltage V. B1 series resistor R B1 The source of the fourth transistor M4 is grounded, and its gate is connected in series with capacitor C. G It is then connected to the output port of the fourth resonant cavity, and the gate is connected to the voltage V. B1 series resistor R B1 ;

[0020] The drain of the fifth transistor M5 in the third driving unit is connected to the source of the sixth transistor M6, and the connection point is also connected to the input port of the third resonant cavity; the source of the fifth transistor M5 is grounded, and its gate is connected in series with capacitor C. G It is then connected to the output port of the first resonant cavity, and the gate is connected to the voltage V. B1 series resistor R B1 The drain of the sixth transistor M6 is grounded, and its gate is connected in series with capacitor C. G It is then connected to the output port of the second resonant cavity, and the gate is connected to the voltage V. B1 series resistor R B1 ;

[0021] The drain of the seventh transistor M7 in the fourth driving unit is connected to the source of the eighth transistor M8, and the connection point is also connected to the input port of the fourth resonant cavity; the source of the seventh transistor M7 is grounded, and its gate is connected in series with capacitor C. G It is then connected to the output port of the third resonant cavity, and the gate is connected to the voltage V. B1 series resistor R B1 The drain of the eighth transistor M8 is grounded, and its gate is connected in series with capacitor C. G It is then connected to the output port of the third resonant cavity, and the gate is connected to the voltage V. B1 series resistor R B1 .

[0022] Beneficial Effects: Compared with the prior art, the significant technical effects of this invention are as follows: It proposes a series resonant oscillator based on coupled inductors, which is divided into four stages, each with a completely identical structure. Each stage includes a resonant cavity and a driving unit. The output of the first-stage resonant cavity serves as the input of the second and third-stage driving units, the output of the second-stage resonant cavity serves as the input of the third and fourth-stage driving units, the output of the third-stage resonant cavity serves as the input of the first and fourth-stage driving units, and the output of the fourth-stage resonant cavity serves as the input of the first and second-stage driving units, forming a loop. This achieves phases of the output voltage signals of the first to fourth resonant cavities of 0°, 90°, 180°, and 270°, respectively. The first and third-stage resonant cavities are inductively coupled, and the second and fourth-stage resonant cavities are inductively coupled to form differential output resonant cavities, thereby reducing the chip area. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a traditional series resonant oscillator structure.

[0024] Figure 2 This is a schematic diagram of the inductor layout of a traditional series resonant oscillator.

[0025] Figure 3 This is a schematic diagram of the series resonant oscillator structure described in this invention;

[0026] Figure 4 This is a schematic diagram of the layout of the coupled inductor of the series resonant oscillator described in this invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0028] Traditional series resonant oscillator circuit diagram as follows Figure 1 As shown, this circuit has four independent inductors L1, and its layout is as follows. Figure 2 As shown.

[0029] The oscillator circuit diagram of the present invention is as follows: Figure 3 As shown, this circuit has two sets of coupled inductors, and its layout is as follows. Figure 4 As shown. The oscillator circuit includes four identical resonant cavities and four identical drive units;

[0030] Four identical resonant cavities, namely the first resonant cavity, the second resonant cavity, the third resonant cavity, and the fourth resonant cavity, are formed by mutual inductive coupling between the first and third resonant cavities to form a differential output resonant cavity, and by mutual inductive coupling between the second and fourth resonant cavities to form a differential output resonant cavity; thereby reducing the chip area.

[0031] Specifically, the first, second, third, and fourth resonant cavities each include an inductor L1 and a frequency tuning module. The two ends of the inductor L1 are connected to the input and output ports of the resonant cavity, respectively. The output terminal of the frequency tuning module is connected to the output port of the resonant cavity, and the control terminal is connected to the control voltage V. CON The third terminal is connected to the third terminal of another frequency tuning module located in the same differential output resonant cavity; the inductors L1 of the first and third resonant cavities are mutually coupled, as are the inductors L1 of the second and fourth resonant cavities. The frequency tuning module is used to adjust the frequency of the output voltage signal of each resonant cavity. Inductive coupling improves the quality factor of the resonant cavity, further suppresses phase noise, and improves the overall performance of the oscillator.

[0032] The frequency tuning module includes a switched capacitor array and a variable capacitor array. One end of the switched capacitor array is connected to the output port of the resonant cavity, and the other end is connected to the third terminal of the frequency tuning module. One end of the variable capacitor array is connected to the output port of the resonant cavity, and the other end is connected to the control terminal of the frequency tuning module.

[0033] The switched capacitor array includes a second capacitor C1 and multiple switched capacitor series modules connected in parallel, wherein each switched capacitor series module includes a first capacitor C connected in series. SCA And switch SW1, the other end of switch SW1 is connected in series with another switch SW1 located in the same differential output resonant cavity, and the first capacitor C SCA The other end is connected to the output port of the resonant cavity, and the second capacitor C1 is connected in parallel with the switch SW1; the variable capacitor array includes a third capacitor C2 and a variable capacitor C connected in series. var Variable capacitor C var The other end is connected to the control voltage V CON Connect the other end of the third capacitor C2 to the output port of the resonant cavity.

[0034] like Figure 3 As shown, in an exemplary embodiment, the switched capacitor array includes three switched capacitor series modules connected in parallel. The three dashed boxes in the figure represent the three switched capacitor series modules connected in parallel.

[0035] In one exemplary embodiment, the other end of switch SW1 is connected in series with another switch SW1 located in the same differential output resonant cavity and grounded. That is, the two capacitors C1 in the frequency tuning modules of the first and third resonant cavities can be grounded or directly connected without grounding. It should be noted that grounding will reduce the quality factor of the resonant cavity.

[0036] In one exemplary embodiment, the frequency tuning module further includes a resistor R. B2 resistance R B2 One end is connected to the third capacitor C2 and the variable capacitor C var The series connection point is connected, and the other end is connected to the voltage V. B2 connect.

[0037] Add resistor R B2 This can be given to the variable capacitor C. var A given bias voltage can affect the variable capacitor C. var The capacitance value affects the operating frequency of the oscillator.

[0038] In one exemplary embodiment, the first resonant cavity, the second resonant cavity, the third resonant cavity, and the fourth resonant cavity further include a fourth capacitor C. D1 Two fourth capacitors C are connected in series between the input ports of the first and third resonant cavities. D1 Two fourth capacitors C are connected in series between the input ports of the second and fourth resonant cavities. D1 .

[0039] In one exemplary embodiment, the first resonant cavity, the second resonant cavity, the third resonant cavity, and the fourth resonant cavity all further include a fifth capacitor C. D2 The fifth capacitor C D2 It is connected in parallel across the inductor L1.

[0040] In one exemplary embodiment, the first resonant cavity, the second resonant cavity, the third resonant cavity, and the fourth resonant cavity further include a fourth capacitor C. D1 and the fifth capacitor C D2 Two fourth capacitors C are connected in series between the input ports of the first and third resonant cavities. D1 Two fourth capacitors C are connected in series between the input ports of the second and fourth resonant cavities. D1 Fifth capacitor C D2 It is connected in parallel across the inductor L1.

[0041] It should be noted that the two fourth capacitors C connected in series... D1 They can be directly connected or grounded, but direct connection is more effective.

[0042] By introducing two additional types of parallel capacitors C D1 and / or C D2 The impedance network of the resonant cavity in series resonance was changed to a resonant cavity impedance network that combines parallel resonance and series resonance. This increased the equivalent parallel impedance of the resonant cavity and reshaped the impedance network of the resonant cavity. As a result, under the same supply voltage, power consumption was reduced, phase noise was suppressed, and the overall performance of the oscillator was improved. Four identical driving units are designated as a first driving unit, a second driving unit, a third driving unit, and a fourth driving unit. The first driving unit outputs a first current signal to a first resonant cavity, which converts the first current signal into a first voltage signal. This first voltage signal serves as the input signal for both the second and third driving units. The second driving unit outputs a second current signal to a second resonant cavity, which converts the second current signal into a second voltage signal. This second voltage signal also serves as the input signal for both the third and fourth driving units. The third driving unit outputs a third current signal to a third resonant cavity, which converts the third current signal into a third voltage signal. This third voltage signal serves as the input signal for both the fourth and first driving units. The fourth driving unit outputs a fourth current signal to a fourth resonant cavity, which converts the fourth current signal into a fourth voltage signal. This fourth voltage signal serves as the input signal for both the first and second driving units. The first and third voltage signals form a differential signal, as do the second and fourth voltage signals. The phases of the first, second, third, and fourth voltage signals are 0°, 90°, 180°, and 270°, respectively.

[0043] Specifically, the first driving unit, the second driving unit, the third driving unit, and the fourth driving unit each include two transistors and two capacitors C. G and two resistors R B1 The source of the first transistor M1 in the first driving unit is connected to the drain of the second transistor M2, and the connection point is also connected to the input port of the first resonant cavity; the drain of the first transistor M1 is connected to the power supply, and the gate is connected in series with a capacitor C. G It is then connected to the output port of the fourth resonant cavity, and the gate is connected to the voltage V. B1 series resistor R B1 The source of the second transistor M2 is grounded, and its gate is connected in series with capacitor C. G It is then connected to the output port of the second resonant cavity, and the gate is connected to the voltage V. B1 series resistor R B1 Transistors are used to amplify signals and provide energy to maintain oscillations; capacitor C G Used for voltage division to reduce the voltage amplitude at the transistor gate and prevent the transistor from being damaged. Resistor R B1This involves applying a defined DC voltage to the gate of the transistor externally through the resistor.

[0044] The source of the third transistor M3 in the second driving unit is connected to the drain of the fourth transistor M4, and the connection point is also connected to the input port of the second resonant cavity; the drain of the third transistor M3 is connected to the power supply, and its gate is connected in series with a capacitor C. G It is then connected to the output port of the first resonant cavity, and the gate is connected to the voltage V. B1 series resistor R B1 The source of the fourth transistor M4 is grounded, and its gate is connected in series with capacitor C. G It is then connected to the output port of the fourth resonant cavity, and the gate is connected to the voltage V. B1 series resistor R B1 ;

[0045] The drain of the fifth transistor M5 in the third driving unit is connected to the source of the sixth transistor M6, and the connection point is also connected to the input port of the third resonant cavity; the source of the fifth transistor M5 is grounded, and its gate is connected in series with capacitor C. G It is then connected to the output port of the first resonant cavity, and the gate is connected to the voltage V. B1 series resistor R B1 The drain of the sixth transistor M6 is grounded, and its gate is connected in series with capacitor C. G It is then connected to the output port of the second resonant cavity, and the gate is connected to the voltage V. B1 series resistor R B1 ;

[0046] The drain of the seventh transistor M7 in the fourth driving unit is connected to the source of the eighth transistor M8, and the connection point is also connected to the input port of the fourth resonant cavity; the source of the seventh transistor M7 is grounded, and its gate is connected in series with capacitor C. G It is then connected to the output port of the third resonant cavity, and the gate is connected to the voltage V. B1 series resistor R B1 The drain of the eighth transistor M8 is grounded, and its gate is connected in series with capacitor C. G It is then connected to the output port of the third resonant cavity, and the gate is connected to the voltage V. B1 series resistor R B1 .

[0047] The working principle and process of the series resonant oscillator based on coupled inductors described in this invention are as follows: The oscillator utilizes an inductor and a capacitor to form a resonant circuit, and leverages the amplification characteristics of an active device, the transistor, to maintain oscillation. In the circuit, the thermal noise or transient interference of the resonant cavity serves as the initial signal. After amplification by the transistor, it is fed back to the next stage resonant cavity. Each stage resonant cavity provides a 90° phase shift. After four stages of resonant cavities, the initial signal returns to the origin, with a total phase shift of 360° and a loop voltage gain greater than or equal to 1, satisfying the Barkhausen criterion. Thus, the circuit achieves stable self-excited oscillation. Because each stage resonant cavity provides a 90° phase shift, the oscillator can provide signal outputs with four phases: 0°, 90°, 180°, and 270°. Furthermore, the resonant cavity of this series resonant oscillator consists of an inductor and a capacitor connected in series. This resonant cavity design (i.e., inductor L1, second capacitor C1, and fixed capacitor C) SCA The design can reduce the equivalent parallel impedance of the resonant cavity, thereby enabling a larger voltage swing and lower phase noise.

[0048] This invention transforms two independent inductors L1 into a coupled inductor by inductive coupling, thus changing the layout of the four inductors from... Figure 2 Become Figure 4 The use of coupled inductors has the following effects: (1) reducing the layout area by nearly half and lowering costs; (2) increasing the equivalent inductance of the inductor, thereby improving the quality factor and helping to reduce phase noise.

[0049] Switch SW1, fixed capacitor C SCA C1, C2 and variable capacitor C var Together, they form the frequency tuning section. This includes switch SW1 and fixed capacitor C. SCA C1 and C2 together form a switched capacitor array, enabling coarse tuning of the oscillator's operating frequency. This is achieved by adjusting V... CON The voltage can change the variable capacitor C. var The capacitance value is determined to achieve continuous fine-tuning of the operating frequency. Fixed capacitors C1 and C2 act as voltage dividers in the circuit, preventing the variable capacitor C from being overloaded. var The voltage swing at switch SW1 was too large, causing it to break down.

[0050] This invention additionally introduces a fixed capacitor C D1 C D2 These two capacitors alter the impedance network of the resonant cavity. Generally speaking, the quality factor of a fixed capacitor is higher than that of a switched capacitor array and a varactor capacitor. Therefore, the fixed capacitor C... D2 This also improves the quality factor of the resonant cavity, reducing power consumption while maintaining phase noise performance. This is achieved by introducing a fixed capacitor C. D1 C D2 This achieves the effect of improving the overall performance of the series resonant oscillator.

[0051] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the term "comprising" or any other variations thereof is intended to cover non-exclusive inclusion, such that an article or device comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device comprising said element.

[0052] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A series resonant oscillator based on a coupled inductor, characterized in that, include: Four resonant cavities with identical structures are designated as the first resonant cavity, the second resonant cavity, the third resonant cavity, and the fourth resonant cavity. The first resonant cavity and the third resonant cavity are mutually inductively coupled to form a differential output resonant cavity, and the second resonant cavity and the fourth resonant cavity are mutually inductively coupled to form a differential output resonant cavity. Four identical driving units are designated as a first driving unit, a second driving unit, a third driving unit, and a fourth driving unit. The first driving unit outputs a first current signal to a first resonant cavity, which converts the first current signal into a first voltage signal. This first voltage signal serves as the input signal for both the second and third driving units. The second driving unit outputs a second current signal to a second resonant cavity, which converts the second current signal into a second voltage signal. This second voltage signal also serves as the input signal for both the third and fourth driving units. The third driving unit outputs a third current signal to a third resonant cavity, which converts the third current signal into a third voltage signal. This third voltage signal serves as the input signal for both the fourth and first driving units. The fourth driving unit outputs a fourth current signal to a fourth resonant cavity, which converts the fourth current signal into a fourth voltage signal. This fourth voltage signal serves as the input signal for both the first and second driving units. The first and third voltage signals form a differential signal, as do the second and fourth voltage signals. The phases of the first, second, third, and fourth voltage signals are 0°, 90°, 180°, and 270°, respectively.

2. The series resonant oscillator based on coupled inductors according to claim 1, characterized in that, The first, second, third, and fourth resonant cavities each include an inductor L1 and a frequency tuning module. The two ends of the inductor L1 are connected to the input and output ports of the resonant cavity, respectively. The output terminal of the frequency tuning module is connected to the output port of the resonant cavity, and the control terminal is connected to the control voltage V. CON The third terminal is connected to the third terminal of another frequency tuning module located in the same differential output resonant cavity; the inductors L1 of the first resonant cavity and the third resonant cavity are mutually coupled, and the inductors L1 of the second resonant cavity and the fourth resonant cavity are mutually coupled. The frequency tuning module is used to adjust the frequency of the output voltage signal of each resonant cavity.

3. The series resonant oscillator based on coupled inductors according to claim 2, characterized in that, The frequency tuning module includes a switched capacitor array and a variable capacitor array. One end of the switched capacitor array is connected to the output port of the resonant cavity, and the other end is connected to the third terminal of the frequency tuning module. One end of the variable capacitor array is connected to the output port of the resonant cavity, and the other end is connected to the control terminal of the frequency tuning module.

4. The series resonant oscillator based on coupled inductors according to claim 3, characterized in that, The switched capacitor array includes a second capacitor C1 and multiple switched capacitor series modules connected in parallel, wherein each switched capacitor series module includes a first capacitor C connected in series. SCA And switch SW1, the other end of switch SW1 is connected in series with another switch SW1 located in the same differential output resonant cavity, and the first capacitor C SCA The other end is connected to the output port of the resonant cavity, and the second capacitor C1 is connected in parallel with the switch SW1; the variable capacitor array includes a third capacitor C2 and a variable capacitor C connected in series. var Variable capacitor C var The other end is connected to the control voltage V CON Connect the other end of the third capacitor C2 to the output port of the resonant cavity.

5. The series resonant oscillator based on coupled inductors according to claim 4, characterized in that, The other end of switch SW1 is connected in series with another switch SW1 located in the same differential output resonant cavity and grounded.

6. The series resonant oscillator based on coupled inductors according to claim 3, characterized in that, The frequency tuning module also includes resistor R B2 resistance R B2 One end is connected to the third capacitor C2 and the variable capacitor C var The series connection point is connected, and the other end is connected to the voltage V. B2 connect.

7. The series resonant oscillator based on coupled inductors according to claim 2, characterized in that, The first resonant cavity, the second resonant cavity, the third resonant cavity, and the fourth resonant cavity also include a fourth capacitor C. D1 Two fourth capacitors C are connected in series between the input ports of the first and third resonant cavities. D1 Two fourth capacitors C are connected in series between the input ports of the second and fourth resonant cavities. D1 .

8. The series resonant oscillator based on coupled inductors according to claim 7, characterized in that, The first resonant cavity, the second resonant cavity, the third resonant cavity, and the fourth resonant cavity also include a fifth capacitor C. D2 The fifth capacitor C D2 It is connected in parallel across the inductor L1.

9. The series resonant oscillator based on coupled inductors according to claim 2, characterized in that, The first resonant cavity, the second resonant cavity, the third resonant cavity, and the fourth resonant cavity also include a fifth capacitor C. D2 The fifth capacitor C D2 It is connected in parallel across the inductor L1.

10. The series resonant oscillator based on coupled inductors according to claim 1, characterized in that, The first driving unit, the second driving unit, the third driving unit, and the fourth driving unit each include two transistors and two capacitors C. G and two resistors R B1 The source of the first transistor M1 in the first driving unit is connected to the drain of the second transistor M2, and the connection point is also connected to the input port of the first resonant cavity; the drain of the first transistor M1 is connected to the power supply, and the gate is connected in series with a capacitor C. G It is then connected to the output port of the fourth resonant cavity, and the gate is connected to the voltage V. B1 series resistor R B1 The source of the second transistor M2 is grounded, and its gate is connected in series with capacitor C. G It is then connected to the output port of the second resonant cavity, and the gate is connected to the voltage V. B1 series resistor R B1 ; The source of the third transistor M3 in the second driving unit is connected to the drain of the fourth transistor M4, and the connection point is also connected to the input port of the second resonant cavity; the drain of the third transistor M3 is connected to the power supply, and its gate is connected in series with a capacitor C. G It is then connected to the output port of the first resonant cavity, and the gate is connected to the voltage V. B1 series resistor R B1 The source of the fourth transistor M4 is grounded, and its gate is connected in series with capacitor C. G It is then connected to the output port of the fourth resonant cavity, and the gate is connected to the voltage V. B1 series resistor R B1 ; The drain of the fifth transistor M5 in the third driving unit is connected to the source of the sixth transistor M6, and the connection point is also connected to the input port of the third resonant cavity; the source of the fifth transistor M5 is grounded, and its gate is connected in series with capacitor C. G It is then connected to the output port of the first resonant cavity, and the gate is connected to the voltage V. B1 series resistor R B1 The drain of the sixth transistor M6 is grounded, and its gate is connected in series with capacitor C. G It is then connected to the output port of the second resonant cavity, and the gate is connected to the voltage V. B1 series resistor R B1 ; The drain of the seventh transistor M7 in the fourth driving unit is connected to the source of the eighth transistor M8, and the connection point is also connected to the input port of the fourth resonant cavity; the source of the seventh transistor M7 is grounded, and its gate is connected in series with capacitor C. G It is then connected to the output port of the third resonant cavity, and the gate is connected to the voltage V. B1 series resistor R B1 The drain of the eighth transistor M8 is grounded, and its gate is connected in series with capacitor C. G It is then connected to the output port of the third resonant cavity, and the gate is connected to the voltage V. B1 series resistor R B1 .

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